Device blocked for no reason

I have a device that my husband purchased from MTN on contract. It is an iPhone 11. It just suddenly stopped working in 2022 and due to urgency he just bought me a new device. I have been using the device for work purposes because I just needed an internet connection but now I need to use it for normal cellphone use. At the time that I lost signal, he went to an MTN store in Rosebank and I went to one in Eastgate but no one could assist. My cellphone number is ***, I have always used a Vodacom SIM card in the phone, the contract was a device only contract. After not getting any help from MTN I took it to an independent repair store and was told that my device has been blocked from all cellphone networks. When I took the issue up with Vodacom they said this is only something that MTN would do as it is an MTN device. I still haven't been assisted by MTN up until now. My device is in perfect working order, it just has no signal.